The U.S. Navy test-fired a ballistic missile from a nuclear-powered submarine off the coast of California last week as the vessel prepares to return to service, according to the Department of Defense.

Photographs of an unarmed, extended life Trident II D5, launched Sept. 27 by the USS Louisiana and blasting out of the water near San Diego, were released by the DOD the next day.

The test was part of a Demonstration and Shakedown Operation, a final evaluation of the Louisiana’s crew and readiness following a 41-month engineered refueling overhaul at Puget Sound Naval Shipyard, Wash., which concluded in March.

The Louisiana is one of 14 Ohio-class submarines that make up the most survivable leg of America’s nuclear triad, which includes land and air-launched nuclear weapons, according to the DOD.

“Their stealth design makes finding an SSBN (a nuclear-powered ballistic missile submarine) an almost impossible task, giving pause to potential adversaries,” the DOD states on its website. “The Columbia-class SSBN program will begin to replace the Ohio-class SSBNs starting in the early 2030s.”

The Trident II D5 is the latest generation of the Navy’s submarine-launched ballistic missiles and was first deployed in 1990, according to the Center for Strategic and International Studies.

The service plans to keep the missiles in service under a life extension program into the 2080s, according to the center.

Under the New START agreement, each missile may carry up to eight nuclear warheads, either 100-kiloton W76 warheads or the 475-kiloton W88. Each of the 12 Ohio-class subs always in service carries 20 Trident II missiles, according to the center.

Some motors that supported last week’s unarmed flight test were the oldest Trident II D5 motors flown to date, demonstrating their reliability and proven performance, Northrop Grumman said in a news release Monday.

“Northrop Grumman’s strategic motors have provided propulsion success for 191 successful test launches since their deployment to the fleet,” Wendy Williams, company vice president for propulsion systems, said in the release.

The life-extended Trident II D5 is a three-stage missile also carried by British Vanguard-class submarines and will be carried aboard U.S. Columbia-class and British Dreadnought-class subs in the future, the company said.

Northrop Grumman, under a contract from U.S. defense contractor Lockheed Martin, manufactures solid-propulsion motor systems for all three stages of the missile, the company said.

The company has delivered over 2,000 Trident II D5 motors and made nearly 87 million pounds of propellant since production began in 1985, according to the release.